Liner for Lateral Pipe Line

ABSTRACT

Systems and methods for forming and deploying a pipe liner in a pipe main having a service lateral. The line is formed from three pieces of material. The piece of material forming the front top and of the main liner and the front of the lateral line has a cutout at the joint to reduce bunching, which can result in non-uniform liner thickness and may form obstructions at the joint.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Utility patent applicationSer. No. 15/833,388, filed Dec. 6, 2017, which claims benefit of U.S.Provisional Patent Application No. 62/430,642, filed Dec. 6, 2016. Theentire disclosure of all the above documents is incorporated herein byreference.

BACKGROUND OF THE INVENTION Field of the Invention

This disclosure is related to the field of pipe rehabilitation systems,specifically to cured-in-place pipe liners.

Description of the Related Art

Over time, underground pipelines utilized for the transport of fluids,gases, or other materials become damaged, worn or corroded from use andenvironmental factors. In the past, the methodologies utilized forrehabilitating underground pipelines were costly, labor intensive, andusually required the surrounding ground to be excavated to reach thepipe. The damaged section of pipe would then be patched or replaced, andthe excavated ground refilled. This technique is severely disruptive tothe surrounding environment and communities.

To avoid these problems, “trenchless” techniques were developed. Onesuch trenchless technique is cured-in-place pipe, or CIPP. A CIPP lineris a jointless and seamless pipe liner placed inside an existing pipe,referred to in the art as the “host pipe.” CIPP can be used torehabilitate pipes in the water, sewer, gas, and chemical industries. Ina CIPP rehabilitation, a felt tube is saturated with a resin and theninverted or pulled into the host pipe. The resin saturation process isknown as “resin impregnation” or “wet-out.” This is typically done froman upstream access point, such as a manhole. Once in place, theresin-impregnated felt tube is allowed to cure forming a tight-fitting,jointless liner contained within the host pipe. The curing processtypically uses heat or ultraviolet radiation to cure the resin andharden the liner.

An embodiment of this prior art process is depicted in FIG. 1.Underground pipes typically comprise a main service line 101. In thedepicted figure, the main line 101 is buried underground and accessiblethrough a number of vertical tunnels 104. These tunnels 104 areaccessible through an opening 102 at the surface 106. The opening 102may be, for example, a manhole 102. Usually, the main 101 is connectedto one or more service laterals 103, which are small service lines 103that direct flow to/from the main 101 to service points, such as abuilding.

Over time, the main 101 becomes clogged with debris and naturalobstructions, such as roots and pieces of broken pipe. Typically, piperehabilitation begins by cleaning out the main 101. This may be doneusing any number of techniques, ranging from manual removal to use ofremote cleaning technology, such as a high-pressure water jetter. Next,the cleaned pipe 101 interior is visually inspected, such as by using aremote camera system. This system is generally a mobile closed circuitcamera system providing illuminated real-time images of the pipe 101interior to a remote operator by wired or wireless connection. In thisstage, the camera inspects the pipe 101 interior for remaining debris,or other problems that could inhibit the proper installation of a CIPPliner. The camera can also identify the location, size, and direction ofactive service connections 103.

Once the pipe 101 is cleaned and ready to accept a liner, a liner isimpregnated with resin. The liner itself is generally a felt tube,generally made of polyester, fiberglass cloth, or another materialsuitable for resin impregnation. The resin impregnation process rangesfrom simple to sophisticated. In a simple embodiment, a set of rollersis used to distribute the resin over the tube. However, prevailingindustry standards recommend that the tube be vacuum-impregnated, suchas by a vacuum pump. This is because an uneven or incompletedistribution of resin will result in “dry” areas that do not properlycure, resulting in non-uniform thickness and weak points subject tostructural failure.

Most resins are cured by the application of heat, and may begin to cureat room temperature. Thus, the preferred technique is to cool the lineras it is being impregnated. The liner is generally stored in a cooledenvironment during impregnation, such an ice bath, and is kept chilledfor transportation to the installation site, such as via a refrigeratedtruck. The process of impregnating the liner, known in the art as“wet-out,” may take place onsite, such as in a specially designed mobilewet-out vehicle, but is more commonly performed at a special-purposefacility and trucked cold to the installation site.

The wet-out process typically involves feeding the liner through acalibrated roller to apply the resin, preferably with a vacuum-assist toremove and minimize trapped air. Next, the saturated liner is wound on aroller in an inversion tank. This typically involves sealing the linerat one end, and attaching a pullback line to the sealed end. The lineris then rolled onto the roller in the inversion tank. The inversion tankcomprises a pressurized container with an egress pipe at one end. Oncethe saturated liner is rolled into the inversion tank, the lead end ofthe rolled liner is fed out through the egress pipe and the tank issealed. The lead end is folded back or cuffed around the egress pipefrom the tank, which allows the inversion process to begin.

Pressure is applied within the tank via water or air, forcing the linerto invert progressively into the host pipe. Because the liner is stillin a wet state, it can negotiate corners and bends, conforming to theinterior shape of the host pipe. The liner is then cured, usuallythrough the application of hot water, steam, or another source of heat.Once the liner is cured, the ends are cut open and another visualinspection is conducted to confirm that the installation was successful.

One problem with this process is the blocking of service laterals. Whenthe CIPP liner is inserted into the main 101, the deployed liner willblock the connection between the main 101 and the service laterals 103.This is one reason to visually inspect the main 101 to identify thelocation, number, and size of service lateral openings before installingthe CIPP liner. After the CIPP liner has been inserted and cured, aremote cutting device is inserted into the newly lined main 101 to cutholes in the CIPP liner at the appropriate locations to restore serviceto the laterals 103.

However, one problem with this solution process is that gaps can developbetween the CIPP liner and the host pipe 101. This is because resinsshrink upon curing, and the host pipe 101 often is soiled with fats,oils, and/or grease, which inhibit a bond from forming between the resinand the host pipe 101. This creates an annular space between the CIPPliner and the host pipe 101. This space exists in nearly allinstallations using CIPP technology, and varies in size from very smallto significant. When the liner is cut to restore the service laterals103, fluid access to these annular spaces may be provided. This canresult in water, moisture, or other materials tracking through theannular spaces and entering into the fluid stream.

Another problem with prior art solutions concerns service laterals. Inthe prior art, a “top hat” solution is used, where a liner having a“brim” is inserted into the lateral and dried, with the “brim” sealingthe lateral cut. However, this technique results in a weak point at thejoint, susceptible to failure, and a potential protrusion/obstructioncaused by the bunching of liner material around the lateral joint. Othersystems which utilize a single piece liner with a portion for the mainand the lateral pre-connected together are known, but they have aproblem in that the connection is generally at a preformed angle notnecessarily conforming to the actual lateral join. This can result in abunching-up of liner material at the acute angle portion of the lateraljoin. This bunching-up can result in an imperfect liner cure and/orimperfect adhesion to the host as well as presenting a variety ofpossible weak points. Additionally, the presence of seams connecting thevarious parts of the liner together can also create weak points andmaking sure those seams are positioned in places where there is lesslikelihood of concerning failure is something that has not traditionallybeen taken into account.

SUMMARY OF THE INVENTION

The following is a summary of the invention in order to provide a basicunderstanding of some aspects of the invention. This summary is notintended to identify key or critical elements of the invention or todelineate the scope of the invention. The sole purpose of this sectionis to present some concepts of the invention in a simplified form as aprelude to the more detailed description that is presented later.

Because of these and other problems in the art, described herein, amongother things, is a liner configured for trenchless installation in apipe having a service lateral, the liner comprising: a main pipe linerportion comprising a bottom and an opposing top comprising a front topand an opposing back top; and a service lateral liner portion attachedto the main pipe liner portion, the service lateral liner portioncomprising opposing lateral sides and a front and opposing back; whereina first contiguous piece, a second contiguous piece, and a thirdcontiguous piece form the main pipe liner portion and the attachedservice lateral liner portion when assembled together; wherein the firstcontiguous piece comprises the opposing lateral sides and the bottom;wherein the second contiguous piece comprises the front and the fronttop and a cutout portion disposed at the joint between the front and thefront top; and wherein the third contiguous piece comprises the back andthe back top.

In an embodiment, the liner is a cured-in-place pipe.

In another embodiment, the service lateral liner portion is attached tothe main pipe liner portion at a non-perpendicular angle.

In still another embodiment, the first contiguous piece is in theconfiguration of a hexagonal center generally corresponding to thebottom and having two elongated rectangular arms attached at opposingsides of the hexagonal center and generally corresponding to the lateralsides.

In still another embodiment, the first contiguous piece is generallysymmetrical around a midline through the hexagonal portion.

In still another embodiment, the angle from the midline to the majoraxis of each of the arms is the non-perpendicular angle.

In still another embodiment, the second contiguous piece is in theconfiguration of a trapezoidal element corresponding to the front topand attached to a generally rectangular arm corresponding to the front.

In still another embodiment, the cutout portion is disposed at the jointbetween the generally rectangular arm and the trapezoidal element.

In still another embodiment, the cutout portion is generally in theshape of a football formed by a top arc and a connected bottom arc.

In still another embodiment, the top arc is defined by the formula

$y = {( \sqrt{{\frac{25}{64}L^{2}} - x^{2}} ) - {\frac{3}{8}L}}$

wherein L is the length of the major axis of the football shape.

In still another embodiment, the bottom arc is defined by the formula

$y = {{- ( \sqrt{{\frac{25}{64}L^{2}} - x^{2}} )} - {\frac{3}{8}L}}$

wherein L is the length of the major axis of the football shape.

In still another embodiment, the third contiguous piece is in theconfiguration of a trapezoidal element corresponding to the back top andattached to a generally rectangular arm corresponding to the back.

In still another embodiment, the first contiguous piece, the secondcontiguous piece, and the third contiguous piece are made from fabric.

Also described herein, among other things, is a method for forming aliner comprising: providing a first contiguous piece comprising ahexagonal center generally corresponding to a bottom of a main pipeliner and having two elongated rectangular arms generally correspondingto lateral sides of a service lateral liner attached to the main pipeliner, the first contiguous piece being symmetrical around a midline ofthe hexagonal center; providing a second contiguous piece comprising atrapezoidal element corresponding to a front top of the main pipe linerand attached to a generally rectangular aim corresponding to a front ofthe service lateral; providing a third contiguous piece comprising atrapezoidal element corresponding to a back top of the main pipe linerand attached to a generally rectangular arm corresponding to a back ofthe service lateral; removing from the second contiguous piece an amountof material at the joint between the trapezoidal element and theattached generally rectangular arm, the amount of material being in theshape of a football defined by a top arc and an opposing bottom arc; andassembling the first contiguous piece, the second contiguous piece, andthe third contiguous piece form the main pipe liner portion and servicelateral liner attached thereto at the angle between the midline and themajor axis of each of the arms.

In an embodiment, the top arc is defined by the formula

$y = {( \sqrt{{\frac{25}{64}L^{2}} - x^{2}} ) - {\frac{3}{8}L}}$

wherein L is the length of the major axis of the football shape.

In another embodiment, the bottom arc is defined by the formula

$y = {{- ( \sqrt{{\frac{25}{64}L^{2}} - x^{2}} )} - {\frac{3}{8}L}}$

wherein L is the length of the major axis of the football shape.

In still another embodiment, the first contiguous piece, the secondcontiguous piece, and the third contiguous piece are made from fabric.

In still another embodiment, the liner is a cured-in-place pipe.

In still another embodiment, the method further comprising installingthe assembled liner in a pipe main having a service lateral attachedthereto at the non-perpendicular angle such that the main liner linesthe pipe main and the service lateral liner lines the service lateral.

In still another embodiment, the angle is a non-perpendicular angle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a diagram of a prior art cured-in-place pipe (“CIPP”)liner installation process.

FIGS. 2A and 2B provide a diagram of a service lateral liner.

FIG. 3 depicts an embodiment of a CIPP liner for a service lateralaccording to the present disclosure.

FIG. 4A depicts embodiments of front and back pieces for a CIPP linerfor a service lateral according to the present disclosure.

FIG. 4B depicts an embodiment of a bottom/side piece of a CIPP liner fora service lateral according to the present disclosure.

FIG. 4C provides a set of perspective drawings of an embodiment of anassembled CIPP liner for a service lateral comprised of a plurality ofconnected pieces according to the present disclosure.

FIG. 4D depicts a cutaway diagram of an embodiment of a CIPP liner for aservice lateral according to the present disclosure.

FIG. 5A depicts an alternative embodiment of a CIPP liner for a servicelateral according to the present disclosure.

FIG. 5B depicts an alternative embodiment of a bottom and side piece ofa CIPP liner for a service lateral according to the present disclosure.

FIG. 5C depicts a cutaway diagram of an alternative embodiment of a CIPPliner for a service lateral.

FIG. 6 depicts an embodiment of a CIPP liner for a service lateralhaving a cutaway area according to the present disclosure.

FIG. 7 depicts a graph of an embodiment of a cutaway area for use with aCIPP liner according to the present disclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The following detailed description and disclosure illustrates by way ofexample and not by way of limitation. This description will clearlyenable one skilled in the art to make and use the disclosed systems andmethods, and describes several embodiments, adaptations, variations,alternatives and uses of the disclosed systems and methods. As variouschanges could be made in the above constructions without departing fromthe scope of the disclosures, it is intended that all matter containedin the description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

Described herein, among other things, is a CIPP liner including a branchliner for a service lateral which is designed to limit or inhibitmaterial bunching. An embodiment of such a liner is depicted in FIG. 2A.In the depicted embodiment of FIG. 2A, a main liner 109 is disposedwithin a main 101 having at least one service lateral 103. The mainliner 109 includes a lateral liner 201 inverted within the main liner109. To install the lateral liner 201, the main liner 109 is positionedso that the joint between the main liner 109 and lateral liner 201 issituated at the joint 203 between the main line 101 and the servicelateral 103. Next, pressure is applied to cause the branch liner 201 toinvert into the service lateral 103. This is depicted in FIG. 2B. Thisinstallation has the advantage of providing a seamless and jointlessliner between the main 101 and lateral 103, reducing the problems causedby spaces between the liner 109 and main 101.

In FIG. 3, an embodiment of such a liner 109 is shown. In the depictedembodiment of FIG. 3, the liner 109 is constructed of three differentpieces 301, 303A and 303B, which are assembled to form the liner 109. Inthe depicted embodiment, the lateral sides A of the service liner 201and the bottom portion B of the main liner 109 comprise a firstcontiguous piece 301 of liner material. The front D of the service liner201 and the front top C of the main liner 109 comprise a secondcontiguous piece 303A of liner material. The back E of the service liner201 and the back top F of the main liner 109 comprise a third contiguouspiece 303B of liner material. The relative directional terms “front,”“back,” and “lateral sides” should be understood with respect to theaxial length of the main 101, as in, for example, FIG. 3.

The depicted liner 109 is configured for use with a service lateral thatconnects to the main 101 at a non-perpendicular angle θ. In the depictedembodiment, θ is about sixty degrees as measured from the axis of main101.

Pieces 301, 303A, and 303B are further depicted in FIGS. 4A and 4B. Asshown in FIG. 4B, the first piece 301 comprises a generally hexagonalcenter B with two generally rectangular aims A attached thereto andextending therefrom at opposing sides of the hexagon, the piece 301being generally symmetrical at a midline 407. The angle θ between themidline 407 and the major length of the arms A is about the same as theangle θ of the lateral 103 to the main 101. As shown in FIG. 4A, thesecond piece 303A is comprised of a generally rectangular arm Dcorresponding to the front D of the lateral liner 201, and connected toa generally trapezoidal element C corresponding to the front top C ofthe main liner 109. The third piece 303B is also comprised of agenerally rectangular arm E corresponding to the back side E of thelateral liner 201, and is connected to a generally trapezoidal componentF corresponding to the back top F of main liner 109.

To assemble the liner 109, the rectangular arms A of piece 301, shown inFIG. 4B, are folded towards each other, forming the sides A of thelateral liner 201. The hexagon B forms the bottom B of the main liner109. Piece 303B is folded 401 at about the connection point between therectangle E and the trapezoid F, and piece 303A is likewise folded 403at about the connection point between rectangle D with trapezoid C. Thethree pieces 301, 303A and 303B are sewn together to form the depictedliner of FIG. 3. FIG. 4C depicts perspective drawings of the assembledliner 109 showing the corresponding connection of pieces 301, 303A, and303B. Similarly, FIG. 4D depicts a cutaway diagram of the assembledliner 109.

In the depicted embodiment of FIGS. 3 and 4A-4D, the angle θ between theservice lateral 103 and the main line 101 is non-perpendicular. If thefold 403 is made in piece 303A to assemble the liner 109, trapezoidalportion C is at an acute angle to the rectangular portion D. This acuteangle causes the material of piece 303A around the fold 403 to crinkle,or bunch up. This in turn can result in non-uniform thickness, and mayform an obstruction at the joint between the main 101 and servicelateral 103. It is thus desirable to prevent or inhibit bunching up ofthe felt material of the liner tube 109.

To do this, an amount of material is removed 405 at the folding point403. The amount and shape of the material to be removed 405 varies withthe angle and size of the piece, and is generally configured in theshape of two opposing arcs joined at their end points, or a “football”shape. This shape 405 is shown in FIG. 4A, and is shown in more detailin FIG. 6. In the depicted embodiment, the shape 405 of the removedmaterial is defined by two circular arcs, arc_(top) and arc_(bottom). Inthe depicted embodiment, arc_(top) is defined as that portion of thecircular arc defined by Equation 1 located above the x-axis (positivey-value).

$\begin{matrix}{{y = {( \sqrt{{\frac{25}{64}L^{2}} - x^{2}} ) - {\frac{3}{8}L}}}{{where}\mspace{14mu} L\mspace{14mu} {is}\mspace{14mu} {the}\mspace{14mu} {length}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {chord}\mspace{14mu} {at}\mspace{14mu} {the}\mspace{14mu} x\text{-}{axis}}} & {{Equation}\mspace{14mu} (1)}\end{matrix}$

In the depicted embodiment, the shape of arc_(bottom) is defined as thatportion of the circular arc defined by Equation 2 located below thex-axis (negative y-value).

$\begin{matrix}{{y = {{- ( \sqrt{{\frac{25}{64}L^{2}} - x^{2}} )} - {\frac{3}{8}L}}}{{where}\mspace{14mu} L\mspace{14mu} {is}\mspace{14mu} {the}\mspace{14mu} {length}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {chord}\mspace{14mu} {at}\mspace{14mu} {the}\mspace{14mu} x\text{-}{axis}}} & {{Equation}\mspace{14mu} (2)}\end{matrix}$

Illustrative examples of these two arcs, having an L=4, are shown inFIG. 7.

By removing the football-shaped portion 405, bunching is inhibitedbecause the fabric which would normally crinkle or bunch up is no longerpresent. This allows the piece 303A to be assembled in an acute anglewith reduced risk of improper curing or forming an obstruction. Itshould be noted that the length L of the chord defining the midpoint ofthe shape 405 is generally less than the width W of the rectangularportion D of the piece 303A. This allows for at least some amount offabric to remain connecting portions C and D together.

While this technique is perhaps most applicable to an acute angle θ, dueto the propensity for bunching with such an angle, it is also usefulwith any angle, including a perpendicular angle. As shown in thedepicted embodiment of FIG. 5, a liner 109 with a lateral 201 at agenerally perpendicular angle may also use the formulae described inEquations 1 and 2 to cut out an amount of fabric 405 at the foldingpoint 403 in order to reduce or inhibit bunching during assembly. FIG.5B depicts an embodiment of a first piece 301 for use in assembling aperpendicular lateral liner 201, and FIG. 5C depicts a cutaway diagramof an assembled liner 109 having perpendicular lateral 201.

This structure reduces or eliminates the problem of bunching, as thestructures defined by the formulae set forth herein and/or by relatedmathematical formulae as would be understood by one of ordinary skill inthe art, reduce the amount of liner material used to form the lateraljoint, resulting in a smoother, continuous connection with less materialbunching, reducing or eliminating weak points caused by prior artsystems.

While the invention has been disclosed in conjunction with a descriptionof certain embodiments, including those that are currently believed tobe the preferred embodiments, the detailed description is intended to beillustrative and should not be understood to limit the scope of thepresent disclosure. As would be understood by one of ordinary skill inthe art, embodiments other than those described in detail herein areencompassed by the present invention. Modifications and variations ofthe described embodiments may be made without departing from the spiritand scope of the invention.

1. A liner configured for trenchless installation in a pipe having aservice lateral, the liner comprising: a main pipe liner portioncomprising a bottom and an opposing top comprising a front top and anopposing back top; and a service lateral liner portion attached to saidmain pipe liner portion, said service lateral liner portion comprisingopposing lateral sides and a front and opposing back; wherein a firstcontiguous piece, a second contiguous piece, and a third contiguouspiece form said main pipe liner portion and said attached servicelateral liner portion when assembled together; wherein said firstcontiguous piece comprises said opposing lateral sides and said bottom;wherein said second contiguous piece comprises said front and said fronttop and a cutout portion disposed at the joint between said front andsaid front top; and wherein said third contiguous piece comprises saidback and said back top.
 2. The liner of claim 1, wherein said liner is acured-in-place pipe liner.
 3. The liner of claim 1, wherein said servicelateral liner portion is attached to said main pipe liner portion at anon-perpendicular angle.
 4. The liner of claim 3, wherein said firstcontiguous piece is in the configuration of a hexagonal center generallycorresponding to said bottom and having two elongated rectangular armsattached at opposing sides of said hexagonal center and generallycorresponding to said lateral sides.
 5. The liner of claim 4, whereinsaid first contiguous piece is generally symmetrical around a midlinethrough said hexagonal portion.
 6. The liner of claim 5, wherein theangle from said midline to the major axis of each of said arms is saidnon-perpendicular angle.
 7. The liner of claim 3, wherein said secondcontiguous piece is in the configuration of a trapezoidal elementcorresponding to said front top and attached to a generally rectangulararm corresponding to said front.
 8. The liner of claim 7, wherein saidcutout portion is disposed at the joint between said generallyrectangular arm and said trapezoidal element.
 9. The liner of claim 3,wherein said third contiguous piece is in the configuration of atrapezoidal element corresponding to said back top and attached to agenerally rectangular arm corresponding to said back.
 10. The liner ofclaim 1, wherein said first contiguous piece, said second contiguouspiece, and said third contiguous piece are made from fabric.